Vacuum commutation apparatus and methods

ABSTRACT

The present invention provides a method and apparatus for transporting a discrete element. A preferably rotatably driven vacuum commutation zone (or internal vacuum manifold), preferably internal to a preferably independently driven porous vacuum roll or drum is disclosed. The vacuum manifold applies vacuum through pores in the driven porous vacuum roll or puck in order to hold material against an external surface of the vacuum roll or puck. By independently controlling the vacuum commutation zone and the driven porous surface, unique motion profiles of the vacuum commutation zone relative to the driven porous surface can be provided. Micro vacuum commutation port structures are also disclosed.

RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.15/217,677 filed 22 Jul. 2016, now U.S. Pat. No. 10,167,156, whichclaims the benefit of U.S. Provisional Application Ser. No. 62/196,736filed 24 Jul. 2015 and U.S. Provisional Application Ser. No. 62/248,155filed 29 Oct. 2015.

BACKGROUND OF THE INVENTION

The present invention relates to disposable hygiene products and morespecifically, to methods and apparatuses for processing disposablehygiene products such as baby diapers, adult diapers, disposableundergarments, incontinence devices, sanitary napkins and the like.

More specifically, the invention relates to novel vacuum commutation. Apuck or drum is used in a novel way with a novel vacuum applicator.Vacuum, which for the purpose of the following description is defined tomean air pressure that is lower than ambient air pressure, is used inmany parts of a diaper manufacturing process. For instance, during pulpcore formation, ambient air flows through the surface of the formingpockets to the vacuum manifolds. This airflow pulls pulp fibers intoforming pockets on a core forming drum. Elsewhere along themanufacturing process, vacuum is used. For instance, a common method ofapplying discrete pieces of one web to another is by use of aslip-and-cut applicator. A slip-and-cut applicator is typicallycomprised of a cylindrical rotating vacuum anvil, a rotating knife roll,and a transfer device. In typical applications, an incoming web is fedat a relatively low speed along the vacuum face of the rotating anvil,which is moving at a relatively higher surface speed and upon which theincoming web is allowed to “slip”. A knife-edge, mounted on the rotatingknife roll, cuts a off a segment of the incoming web against the anvilface. This knife-edge is preferably moving at a surface velocity similarto that of the anvil's surface. Once cut, the web segment is held by theair pressure differential between the ambient air on the exterior of theweb segment and the vacuum holes on the anvil's face as it is carried atthe anvil's speed downstream to the transfer point where the web segmentis transferred to the traveling web. Vacuum can also be used in vacuumconveyors.

Typical vacuum rolls used in the prior art have rows of vacuum holeswhich are fed by cross-drilled ports, each being exposed to the sourceof vacuum by communications, as the ports move into a zone of negativepressure in a stationary manifold. Such a configuration serves to applyvacuum sequentially to each successive row of holes.

Continual improvements and competitive pressures have incrementallyincreased the operational speeds of disposable diaper converters. Asspeeds increased, the mechanical integrity and operational capabilitiesof the applicators had to be improved accordingly. The prior art isquite successful when processing nonporous or low porosity full-width orsymmetrical webs using vacuum, and vacuum is nearly universally used indiaper production. However, as speeds have increased in manufacturingand raw material webs have become more porous and lighter weight, so toohas vacuum demand increased. Along with significant increase in vacuumdemand comes the expense of powering conventional vacuum formingtechniques, and the noise associated with traditional vacuum pumps.

It is therefore an object of this invention to provide an apparatuswhich can provide a better solution for vacuum commutation. The vacuumcan be used for whatever purpose desired, including maintaining controlover diaper webs or discrete portions of diaper webs, including sectionsof various shapes, and to decrease reliance on traditional vacuumgeneration.

SUMMARY OF THE INVENTION

The present invention provides a method and apparatus for providingcontrolled and preferably zoned vacuum commutation. In one embodiment, arotatably driven vacuum commutation zone (or internal vacuum manifold),is independently driven internal to a preferably porous vacuum roll ordrum. The vacuum manifold applies vacuum through pores in the drivenporous vacuum roll in order to hold material against an external surfaceof the vacuum roll.

The combination porous roll and internal vacuum manifold can be used totransport materials from a pickup position to a deposition position,transport materials in a rotatable or linear fashion, as a surface for aslip/cut operation, or any other way seen fit.

By independently rotating or otherwise moving the internal vacuummanifold and independently rotating or otherwise moving the porousvacuum roll, tightly controlled, yet quickly rotating vacuum controlover zones, can be achieved and achieved sequentially.

Different sequences of rotation of the vacuum manifold relative to theporous roll can be used. The vacuum manifold can accelerate rotationallyrelative to the porous roll, rotate at the same speed as the porousroll, or decelerate or move in reverse relative to the porous roll, alldepending on the desired material transport sequence.

In one embodiment, a pair of porous rolls can be placed in closeproximity and operated in conjunction with one another. In thisembodiment, sequences used are to transfer articles between the tworolls at a common transfer point. In another embodiment, the pickup anddrop off (or acquisition and deposition) points are at differentlocations.

Control of the rotational motion of the vacuum manifold can beaccomplished with a cam. Different cams could produce differentrotational sequences of the vacuum manifold. Control of the rotationalmotion of the vacuum manifold could also be accomplished, for instanceby a servo motor. This configuration would allow for reverse rotationaltravel of the vacuum manifold. Reversing could be done when time in thesequence permits to allow for a longer run up to matched speed.

In a preferred operation sequence, the porous roll rotates at constantspeed. At an acquisition point, a trailing edge of the vacuum manifoldunderlies the leading edge of the article to be transported. After thearticle has transferred to the porous roll, the vacuum manifold thenrotates at the same speed as the porous roll. The porous roll receivesthe discrete object at speed to rotate the discrete object intodeposition position, at which point the leading edge of the vacuummanifold precisely stops rotation, leaving the article to be transportedfree to be placed, deposited, or secondarily transported as desired (forinstance by depositing the article to be transported onto a carrier web,or onto a vacuum conveyor). The trailing edge can then be repositioned.to begin the next pickup/deposition sequence. A series of vacuummanifolds can be supplied about an interior surface of the porous rollto commute vacuum to different peripheral regions of the porous roll.

In summary, the external porous roll rotates such that the surface ofthe roll is traveling at the same speed as the incoming discreteelement. The internal vacuum manifold is controlled such that it stopsrotating when its trailing wall is positioned immediately downstream ofthe pickup point. As the leading edge of the discrete article reachesthe edge of the internal vacuum manifold the air flowing from theatmosphere into the vacuum zone forces the leading edge of the discretearticle to transfer to and be held against the surface of the porousroll. Likewise, the remainder of the discrete article will transfer ontothe porous roll as the porous roll advances.

After the trailing edge of a discrete article is transferred to thesurface of a porous roll, the internal vacuum manifold positioned withinthe porous roll accelerates to match the rotational velocity of theporous roll. The internal vacuum manifold decelerates to a stop when itsleading wall reaches a deposition point and air flowing out of theporous roll into the vacuum zone of the receiving device forces thediscrete article to transfer from the surface of the porous roll onto areceiving device. Likewise, the remainder of the discrete articletransfers onto the receiving device as the discrete article continues toadvance. After the discrete article has transferred to the receivingdevice, the internal vacuum manifold returns to its position downstreamof the pickup point and the cycle repeats.

A transition position where air flow direction switches from inward intoa drum, to outward, is preferably offset either upstream or downstreamof the discrete article transfer positions by a selected amount tocompensate for variations in the system.

In another aspect of the invention, ambient air can flow from the insideof the drum outward to eliminate or minimize overlapping low pressurezones, which in turn will preferably: 1) eliminate or minimize inrushesof air at the edges of a discrete article; 2) produce an airflowdirection that is approximately perpendicular to the surface to whichthe discrete element is riding upon.

In another aspect of the invention, a porous drum is provided withmicro-pores to, preferably: 1) reduce airflow requirements in thesystem; 2) provide more complete sealing of the pores and therebyincrease holding forces on the discrete article; 3) minimize “deadzones” or areas with no inward air flow, between pores to minimize thepotential for discrete article edge flip backs.

In another aspect of the invention, the drums and vacuum chambers havevariable motion profiles. Because of the variable motion profiles, it ispossible to accelerate or decelerate the speed of the unit to change thespacing between the discrete elements being transported.

In another aspect of the invention, multiple units work in conjunction,each unit processing every other discrete article in a continuous streamof discrete articles to change the spacing between discrete articles bylarge amounts such as a 5:1 spacing increase. Discrete product or patchflow enters drum 200. Nested ears come in close to each other, but mustbe deposited far from each other. The rolls could be in line with eachother in the cross direction

In another embodiment, controlled vacuum is applied sequentially to atraveling body, such as a puck or a rotating and revolving puck. Alsodisclosed is a method and apparatus for providing a rotatably drivenmulti-zoned vacuum puck used to turn discrete articles 180 degrees(through rotation of the puck) and transport them from a pickup positionto a deposition position (preferably through revolution of a puck abouta central axis carrying a plurality of pucks). Ah external vacuummanifold is employed to apply vacuum through internal vacuum passages inthe puck when the passages are located in positions between thedownstream side of the pick-up position and the upstream side of thedeposition positron. When a vacuum passage is engaged with the vacuummanifold, ambient air flows into the pores on the surface of the puck inorder to hold material against the puck's external surface. Conversely,when a vacuum passage is not engaged with the vacuum manifold, ambientair flows can flow out of the pores on the surface of the puck.

The vacuum puck rotates such that the surface of the puck is travelingat the same sped as the incoming discrete element. The external vacuummanifold is positioned such that ambient air flows outward through thesurface of the puck at points immediately upstream of the pick-up pointand ambient air flows inward through the pores in the surface of thepuck at points immediately downstream of the pick-up point. As theleading edge of the discrete article reaches the pick-up point, airflowing from the atmosphere into the vacuum puck forces the leading edgeof the discrete article to transfer to and be held against the surfaceof the puck. Likewise, the remainder of the discrete article cantransfer onto the porous roll as the porous roll advances.

After the trailing edge of the discrete article is transferred to thesurface of the vacuum puck, the puck continues to rotate and therebytransports the discrete article to the deposition point. The externalvacuum manifold ends immediately upstream of the deposition point suchthat ambient air flows into the puck upstream of the deposition pointand ambient air flows out of the puck downstream of the depositionpoint. As the leading edge of the discrete article passes the depositionpoint, air flowing out of the puck and into the vacuum zone of thereceiving device forces the discrete article to transfer from thesurface of the porous roll onto the receiving device. Likewise, theremainder of the discrete article transfers onto the receiving device asthe discrete article continues to advance. After the discrete articlehas transferred to the receiving device, the vacuum puck returns to itsoriginal orientation and position upstream of the pickup point and thecycle repeats.

In such a puck system, ambient air can flow from the inside of the puckoutward to: 1) eliminate or minimize overlapping low pressure zoneswhich in turn eliminates or minimizes in-rushes of air at the edges ofthe patch; 2) results in an airflow direction that is approximatelyperpendicular to the surface to which the discrete element is ridingupon. Such a puck system also can utilize micro-pores to: 1) reduceairflow requirements; 2) provide more complete sealing of the pores andthereby increases holding force on the discrete article; and 3) minimizedead zones between pores to minimize the potential for discrete articleedge flip backs.

A process is disclosed that optimizes repeatability of discrete articletransfer from one carrier device to a second carrier device by managingthe direction of the air flow during transfer. The dispersing deviceenables airflow into the surface of the device upstream of the transferposition and out of the surface of the device downstream of the transferposition. Conversely, the receiving device is designed to enable airflowout of the surface of the device upstream of the transfer position andinto the surface of the device downstream of the transfer position. Thisprocess eliminates overlapping low pressure zones and thereby minimizesthe potential for in-rushes of ambient air that can cause the edges ofthe discrete article to be disturbed before, during, and after transferbetween the carrier devices, and also enables the benefits previouslydescribed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a porous roll and internal independentlyrotatable vacuum manifold carrying a discrete component of a disposablearticle between an acquisition point and a deposition point;

FIG. 2 is an exploded view of certain components of the porous roll andinternal independently rotatable vacuum manifold;

FIG. 3 is a side view of the porous roll and internal independentlyrotatable vacuum manifold showing independent rotational capabilities;

FIG. 4 is a side view of the porous roll and internal independentlyrotatable vacuum manifold to which vacuum is applied, with air beingdrawn through the porous roll;

FIG. 5 is a close-up view of exemplary pores of the porous roll;

FIGS. 6-13 are side views of a sequence of operation of the porous rolland internal independently rotatable vacuum manifold transporting adiscrete component of a disposable article between an acquisition pointand a deposition point.

FIG. 14 is a demonstrative side view of rotating bodies and air flowpatterns;

FIG. 15 is a demonstrative side view of rotating bodies and air flowpatterns;

FIG. 16 is a close-up view of one pattern of micro vacuum commutationports;

FIG. 17 is a side view of a puck structure;

FIG. 18 is a side view of a puck structure with micro vacuum commutationports and valved and zoned vacuum commutation porting;

FIG. 19 is a perspective view of a puck for carrying discrete portionsof a web, the puck with micro vacuum commutation ports and valved andzoned vacuum commutation porting;

FIG. 20 is a top perspective view of a puck with the capability of bothrotation and revolution;

FIGS. 21A-21F display a side view of a sequence of operation of ananvil/drum feeding discrete pieces to a series of porous roll/internalvacuum manifold combinations positioned about the drum for passing andspacing discrete pieces to a running web;

FIG. 22 is a top perspective view of an exemplary placement sequence ofdiscrete pieces about sides of a running web;

FIG. 23 is an exemplary transfer drum velocity speed profile for aseries of porous rolls and internal vacuum manifolds during anacquisition and deposition sequence.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Although the disclosure hereof is detailed and exact, to enable thoseskilled in the art to practice the invention, the physical embodimentsherein disclosed merely exemplify the invention which may be embodied inother specific structures. While the preferred embodiment has beendescribed, the details may be changed without departing from theinvention, which is defined by the claims.

Referring now to FIG. 1, a side view of a system 10 comprising a porousroll 12 and internal independently rotatable vacuum manifold 14 carryinga discrete component of a disposable article 50 between an acquisitionpoint 52 and a deposition point 54 is shown.

A conveyor 32 carries discrete components 50 towards an acquisitionpoint 52. At the acquisition point 52, control of the discrete component50 is handed off to a porn us roll and vacuum manifold combination 10.Vacuum is drawn through the vacuum manifold 14, and in particularthrough a hollow shaft of the manifold 14, towards a vacuum applicationzone 16. This vacuum withdrawal action draws air through voids or porespaces 24 of porous roll 12. This in turn draws and retains discretecomponent 50 to an exterior surface of porous roll 12, when desired. Asporous roll 12 rotates, it carries discrete component 50 from theacquisition point 52 to deposition point 54. At deposition point 54,control of the discrete component 50 is handed off to a carrier web orvacuum conveyor or a bonder, shown generally at 60. Alternatively, atdeposition point 54, control of the discrete component 50 can be handedoff to a second porous roll and vacuum manifold combination 10. Twomanifold walls 18 proscribe the circumferential area to which vacuum isapplied to pores 24 of porous roll 12.

Referring now to FIG. 2, the structure of the system 10 is describedmore fully. An independently driven hollow manifold shaft 14 is coupledto a vacuum manifold defined by sidewalls 18 and end walls 20 of thevacuum application zone 16. The vacuum manifold application zone 16 isconfigured to fit within porous roll 12 as shown in FIG. 1, through ashaft void 40 in porous roll 12 receiving independently driven hollowmanifold shaft 14, through which vacuum is drawn. Porous roll 12 isprovided with sidewalls 22 which enable ambient air to enter theinterior of porous roll 12. Nonporous zone 62 can be supplied on theporous roll 12 to delineate a cross-machine direction extent of vacuumcommutation through pores 24. Porous roll 12 is preferably rotatedindependently of the manifold. shaft 14, porous roll 12 being rotated bya drive motor 124 which rotates a drive belt 120 which is coupled to aporous roll driveshaft 122 coupled the porous roll 12. In this manner,it is possible to rotate the manifold shaft 14 and associated vacuumapplication zone 16 independent of the rotation of the porous roll 12.

Referring now to FIG. 3, it is possible to configure the manifoldsidewalls 18 at different circumferential spacings to define differentsmaller or larger zones of vacuum commutation to the exterior surface ofporous roll 12.

Referring now to FIG. 4, a side view of the porous roll 12 and internalindependently rotatable vacuum manifold shaft 14 which vacuum is appliedas shown. Ambient air flows through the porous roll 12, through pores24, toward the lower pressure vacuum application zone 16 to 10 smanifold shaft 14, and particularly through shaft 14 by action of avacuum source (not shown). Motor 124 is operable to rotate shaft 122carrying porous roll 12.

Referring now to FIG. 5, an exemplary size and. configuration of pores24 of the porous roll 12 is shown. It can be seen that preferably pores24 are quite small in order to reduce the amount of air volume requiredof the system, and to prevent airborne contaminants such as pulp flufffibers and non woven plastic fabric fibers from plugging the holes. Inaddition, the exemplary size of the pores 25 should be small enough thatthe fibers of the material in the article being transferred block some,all or preferably a majority of the surface area of each pore andthereby approximates a complete seal at the overlap of the fibers andthe pores. This increases the force that holds the article to the porousroll 12 while reducing vacuum supply sizing. Further, reducing the poresize enables the distance between pores to be reduced while maintainingthe same ratio of total pore opening area to closed (non porous) area ofthe porous drum 12. This minimizes the potential for an edge of thearticle from landing in a non porous area of the porous drum and therebyminimizes the potential for the edge of the article to fold back uponitself because it is not held down against the surface of the porousroll.

Referring now generally to FIGS. 6-13, side views of a sequence ofoperation of the rotatable porous roll and internal independentlyrotatable vacuum manifold transporting a discrete component of adisposable article between acquisition point 52 and a deposition point54 is shown.

Beginning the sequence with reference to FIG. 6, discrete element 50approaches acquisition point 52 at a velocity V1. Trailing manifold wall18 a rotates within porous roll 12, until it reaches a positionimmediately downstream of the acquisition point 52. At that point, thetrailing manifold wall stops, or V2 goes to zero, and remains in thisposition until a leading edge of discrete element 50 reaches acquisitionpoint 52. Referring now to FIG. 7, as porous roll 12 rotates at V3 andmanifold shaft 14 does not rotate, vacuum is applied through pores 24 ofporous roll 12 to carry discrete element 50 from the acquisition point52 to a position where the trailing edge of discrete element. 50 reachestrailing manifold wall 18. Manifold shaft 14 then accelerates to V2 andtransports discrete element 50 to deposition point 54. Referring now toFIG. 8, an a preferable embodiment, the circumferential distance betweenleading manifold wall 18 a and trailing manifold wall 18 b approximatesa machine direction length of discrete element 50; however, thecircumferential distance between leading manifold wall 18 a and trailingmanifold wall 18 b can be longer or shorter than the machine directionlength of discrete element 50. During the portion of the sequence shownin FIGS. 7 and 8, it is preferable that V2 equals V3, namely that themanifold shaft 14 and the porous roll 12 are rotating in the samedirection at the same speed.

Referring to FIG. 7, as the leading edge of discrete element 50 reachesdeposition point 54, rotation of the manifold shaft 14 stops, or V2 goesto zero, whale porous roll 12 continues to rotate at V3. At this point,a handoff sequence begins, where control over discrete element 50 ishanded off to a secondary operation 60 moving discrete element 50 at V4,secondary operation 60 for exemplary purposes comprising depositing thediscrete element 50 to be transported onto a carrier web, or onto avacuum conveyor, to a bonder, to an additional system 10 comprising aporous roll 12 and internal independently rotatable vacuum manifold 14,a bonding unit, or otherwise.

Though not necessary, if desired to assist handoff, in an alternateembodiment (not shown) a blow-off system can be incorporated to operatewith the commutating manifold 16 to positively push air through thepores 24 of porous roll 12. To implement a blow-off system, a rotaryunion can be used to attaching a blow off to the manifold (or evenintegrating it into the internal manifold itself). In another embodiment(not shown), a blow-off could assist to clear the pores 24 of porousrolls 12 of debris (such as material fibers) should debris accumulate inthe pores 24.

Referring to FIG. 10, as the handoff sequence of control over discreteelement 50 continues, V2 remains at zero, while 73 remains constant.Referring to FIG. 11, handoff of discrete element 50 to secondaryoperation 60 is complete. Referring to FIG. 12, the handoff sequence hasconcluded and V2 accelerates from zero to a speed greater than zero, inorder to return trailing edge 18 to acquisition point. 52, as shown inFIG. 13.

In another aspect of the invention, the drums and vacuum chambers havevariable motion profiles. Because of the variable motion profiles, it ispossible to accelerate or decelerate the speed of the unit to change thespacing between the discrete elements being transported. Several motionprofiles of V1, V2, V3 and V4 relative, to one another are possible.Such a motion profile could be: for trailing edge 18 a to wait atmaterial pickup location 52 (V2 is zero), next when portion of discreteelement finishes acquisition at point 52, V2 increases; and the V2 ismatched with V3, also the speed of discrete element 50, and then for V2to exceed V3 on approach to deposition point 54 to allows time to slowmanifold 14 without losing vacuum on the leading edge of the patch or toaccelerate the speed of the patch to V4 in the case where V4 is greaterthan V3; next to reduce V2 to zero at deposition point 54; next torepeat the sequence.

It is possible to use multiple internal vacuum application zones 16 bycreating additional walls 18 a and 18 b, connecting through a void spacein shaft 14.

It is also possible for V2 to be in the opposite direction as V3, ifdesired for control in a preferred motion profile.

In an exemplary embodiment of a system that uses vacuum to hold adiscrete element to the surface of a rotating drum, all of the air thatflows from atmosphere into the pores of the drum. would be oriented suchthat the direction of the airflow would be perpendicular to the sue faceof the drum. Any airflow in the cross machine direction or machinedirection of the system has the potential to create forces on the edgesof the discrete element which can cause the discrete element to foldback upon itself. (The discrete element is most susceptible to have edgefolding occur as the discrete element transfers between drums.)Referring now to FIG. 14, a demonstrative side view of rotating bodies200 and 300 and air flow patterns is shown. Upstream of the tangentbetween the two roils 200 and 300, air into the low pressure zones 202of the upper drum 200 travels from atmosphere and 30× of the lower drum300. If the distance between the surfaces of the drums is adequatelylarge, air can flow from the atmosphere surrounding the drums in adirection approximating perpendicular to the drum surfaces. However, ifthe distance between the drum surfaces is reduced incrementally, adistance will be reached where there is not adequate space between thedrums to enable the air to flow in the optimum direction. As thedistance between the rolls is further reduced, the direction of theairflow into the drum surfaces becomes less perpendicular to the drumsurfaces and the potential for discrete element fold over increases.Atmospheric air can enter the system from the upstream side of tangentpoint of the drums 200 and 300, and some air can rush downstream fromthe higher pressure zone towards the downstream side of the transferpoint (not shown). Because so much air as drawn in to create the lowpressure zone in prior art vacuum system design, air velocity canundesirably cause patches carried by the drum (not shown) to behaveerratically, and lead to flipping over of leading, trailing, or sideedges. It has been found that even a small change in the air conditionsat the transfer point can create imperfections and unrepeatability. Tosolve this problem, the system of the present invention limits theamount of airflow in the zone on the upstream side of the tangent partof the rolls 200 and 300, so the system does not undesirably reducepressure, causing air to inrush. Because the bottom drum 300 of thepresent invention supplied at least in part at atmospheric pressure, aircan flow from the interior region of the bottom drum 300 to satisfy theneed for air in the low pressure area 202 of the top drum 200.

FIG. 15 as a demonstrative side view of rotating bodies 200 and 300 andair flow patterns, with this configuration showing two low pressurezones 202 and 302, one in each of the top and bottom rotating drums 200and 300 respectively. A patch 50 is shown being transferred. from thetop drum 200 to the bottom drum 300, but it is understood that in anoperating system, the handoff of the patch 50 is going to be upstreamhandoff to a downstream unit in the machine direction.

To optimize the air flow of the system and minimize undesirable a flowpatterns, it has been found advantageous to avoid locating low pressurezones 202 and 302 opposite of one another in a rotating system. Avoidingadjacent low pressure zones allows atmospheric air to flow into the lowpressure zones 202 and 302 as intended, without undesirable turbulencethat could be transmitted to the carried web or patch.

As shown in FIG. 15, low pressure zone 202 on the top drum 200 leads upto the tangent point between the top drum 200 and bottom drum 300, and alow pressure zone 302 trails the tangent point on the bottom roll 300.It has been found that this configuration minimizes the undesirableinrush of air from the upstream side of the tangent point. Downstream ofthe tangent point, the interior (center) of the top drum 200 is exposedto atmospheric pressure, and this zone assists to satisfy air demandinto the low pressure zone 302 of the bottom drum 300. Conversely,upstream of the tangent point, the interior (center) of the bottom drum300 is exposed to atmospheric pressure, and this zone assists to satisfyair demand into the low pressure zone 202 of the top drum 200. Thegeneral principle is that it has been found advantageous in materialhandling to avoid low pressure zones opposite of one another whilehandling a web or a patch 50.

FIG. 16 is a close-up view of one pattern of micro vacuum commutationports 24. In some systems, drums or other carrying structures (such aspucks) have vacuum commutation ports that have sparsely spaced portconfigurations, with the ports sometimes spaced around the perimeter ofa discrete patch of material (or continuous webs) to be carried by thestructure. In the present invention, micro vacuum commutation ports 24can be used. These micro vacuum commutation ports 24 can have a patterndensity more evenly distributed across the entire surface of the patch(in contrast to around the periphery). Because the system of the presentinvention can use less air (and energy, and in turn create less noise),a smaller amount of airflow is required to be generated by the vacuumsystem. In the present invention, a smaller hole diameter (for example,on the order of 0.003″-0.015″) can generate the holding force necessaryto hold webs commonly used in the manufacturing process, such asnon-woven webs. Such hole diameters result in a surface area of arepresentative void space of between about 7×10−6 square inches and1.8×10−4 square inches each. This pore size has been discovered to beadvantageous to securely hold individual fibers of a typical nonwoven ofa denier of less than 1, to approximately 20 denier, and in somepreferred nonwovens, 10-60 μm diameter; however other nonwovens have 0.1μm diameter-300 μm diameter. Typical nonwoven construction comprisesmany tiny bond points to which connect individual fibers of theessentially random fiber orientation. The microporous structuresdescribed above advantageously align with a holding force effectiveamount of these bond points in nonwoven to provide secure control overnonwovens.

A porous structure, such as drums 200, 300, or any of the disclosedpucks, can be provided with micro vacuum commutation ports 24 to,preferably: 1) reduce airflow requirements in the system; 2) providemore complete sealing of the pores and thereby increase holding forceson the discrete article; 3) minimize “dead zones” or areas with noinward air flow, between pores to minimize the potential for discretearticle edge flip backs.

Such small micro vacuum commutation ports 24 can be manufactured forinstance by electron drilling techniques, chemically etched, or drilledon thin foil. The thin foil construction, if used, is preferablysupported by an underlying support structure for providing rigidity tothe surface of the puck or drum. These techniques can require fairlythin gauge metal to be used in construction of the article carryingsurfaces, resulting in a mask type structure which may be used over afull vacuum zone to limit inertia. In this embodiment, an air-permeablecylinder wall, or a buildup of air-permeable support structure could becovered by a micro-pore screen containing micro vacuum commutation ports24. Such a mask type structure could be desired for instance, in highspeed applications, to reduce inertia.

Non-woven material commonly used in disposable product manufacturing(e.g., diapers, feminine hygiene products) has individual fiberdiameters of in the range of approximately 0.005″. In the prior artvacuum commutation port designs, a port of, for instance, ⅛″ diameter(which can be less or more) causes air to flow around the fibers of thenonwoven, and through the nonwoven. generally. The holding force ofvacuum commutation ports of the prior art is referred to as vacuum,though the holding force is more wind resistance applied to the nonwoventhan true vacuum. In the present invention, micro vacuum commutationports 24, which are near in size or smaller than the fibers of thenonwoven causes the micro vacuum commutation ports covered by anindividual fiber of the nonwoven to be sealed off partially orcompletely. The micro vacuum commutation port 24 arrangement of thepresent invention does not rely as much, if at all, on air flow or windresistance like the prior art, but instead on a static pressuredifferential.

The micro vacuum commutation ports 24 of the present invention are riotnecessarily as small as individual fibers, although such small ports 24are useful and within the scope of the present invention. For instance,spunbond nonwoven has overlapping individual fibers, which can beembossed and bonded to one another.

The micro vacuum commutation ports 24 of the present invention can besized smaller than the bond patters of the spunbond nonwovens. By usingmicro vacuum commutation ports 24 of the present invention, it has beenfound that it is not necessary to engage each fiber, or each bondbetween fibers, and it is likewise not necessary that each micro vacuumcommutation port have an overlying fiber. Sufficient holding force canbe generated by the micro vacuum commutation ports 24 if, for any givendiscrete portion of a web, or a segment of a continuous web, a fractionof the fibers are coupled with a fraction of the micro vacuumcommutation ports 24 in the targeted area to be carried and controlled(e.g., transferred, deposited).

Regarding density of the micro vacuum commutation ports 24 on a givenstructure, micro vacuum commutation ports 24 can be configured tocomprise between 5%-50% of the surface area of the carrying structure(e.g., puck or drum). This range of surface area has been found tofirst, provide sufficient vacuum holding force; yet second, to retainenough strength for durable operation.

One additional benefit of the micro vacuum commutation port structure 24is that the article carrying structure is less prone to contaminationfrom pulp fiber and dust, because the micro vacuum commutation portstructure is so small that it is difficult for contaminants to enter thestructure.

Referring now to FIG. 17 is a side view of a prior art puck structure500 is shown.

In the configuration exemplified by FIG. 17, ambient air leaves a lowpressure zone upstream of the tangent between puck 500 and rotating drum400. Because surfaces of both puck 500 and drum 400 are open to a vacuumchamber, this results in a low pressure zone between surfaces, whichundesirably causes air to inrush from the sides and ends of thesurfaces. The ambient air inrush from between where air is drawn intodrum 400, and where air is drawn into puck 500 can disturb a patch on adrum 400 or puck or being as the patch is transferred. In the currentsystem, at the moment of transfer, and at the transfer point, a transferassist sequence (shown in arrows leaving the interior of drum 400)assists patch or web transfer from drum 400 onto puck 500 (or off of apuck as the case may be) by using a blast of pressurized air at thatspecific location (the transfer point) to blow the patch off the drum500 and. onto the puck 400 receiving the patch. The pressurized air fromdrum 400 can undesirably blow into the puck 500, and the extra airmovement challenges the efficacy of the transfer or patch handoff.

In some prior art puck systems, two zones 1 and 2 are created at thepuck surface, so that vacuum to these zones 1 and 2 can be independentlycontrolled. Zone 1 can have applied vacuum while zone 2 has no appliedvacuum. Alternatively, zone 2 can have applied vacuum while zone 1 hasno applied vacuum. The on/off sequence is principally dictated bywhether the puck 500 is receiving a patch or handing off a patch. It isdesirable in certain handoff or receiving operations to, at a leadingedge of the puck 500 in zone 1, apply vacuum to receive the leading edgeof the received patch. But when it comes time to hand off the patch tothe next equipment downstream, it is desirable to turn vacuum off ofzone 1 to hand the patch off and relinquish control of the patch to thenext piece of equipment, while retaining the patch with vacuum appliedin zone 2. The desired blow-off to assist patch handoff can undesirablyminimize the vacuum present in the puck 500 in zone 1 at that point.

In conventional vacuum puck designs, the pucks have cross machinedirection air chambers that are connected to the surface of the puck500. As the puck 500 travels, the air chambers move between high and lowpressure zones of a vacuum manifold, and this results in air flowinginto or out of the surface of the puck 500. This airflow and theassociated pressure differentials will either cause a material patch tobe attracted or repelled from the puck surface 500.

Still referring to FIG. 17, one shortcoming of the prior art is thatports 502 which commute vacuum to puck 500 are located remotely from thepuck 500. The control for turning vacuum on or off at zones 1 and 2 istherefore remote from the puck 500. This remote arrangement undesirablycreates lag time for high speed switching of vacuum on and off in zones1 and 2. Because some of the turner pucks of the prior art, for instancethose disclosed in U.S. Pat. No. 8,112,977 (incorporated by reference),rotate both in the machine direction and cross machine direction at thesame time, it is impractical to use a conventional combination of a sidevacuum manifold aligning with cross machine direction air chambers.Therefore, the air passages between the puck 500 and the vacuum chamberare routed through the center of the pucks 500. This results inrelatively long airflow passage ways between the surface of the puck 500and the vacuum supply manifold (not shown). This restricts the speed atwhich the direction of airflow at the surface of the puck 500 can bereversed. The remoteness of the vacuum manifold from the puck 500 isdifficult to implement with pucks with multiple discrete zones thatrequire quick changes in airflow direction.

Referring still to FIG. 18, a side view of a puck structure 610 withmicro vacuum commutation ports 24 and valved and zoned vacuumcommutation porting is shown. As with the example shown in FIG. 15 oftwo adjacent vacuum rolls that transfer a patch of material from oneroll to the other roll, the same airflow and micro-perforated surfaceimprovements can be made to a system that replaces one or both of thefull rolls with. vacuum pucks 610 that behave as partial rolls.

Instead of two zones 1 and 2 of the system shown in FIG. 17, the puck610 of FIG. 18 can be made with multiple zones, 1′-10′ or more or lessfor instance. Zones 1′-10′ can either be open to the vacuum chamber (notshown) through ports 502 or open to the atmosphere. With the segmentedvacuum zone 1-10 configuration on the puck 610, the system requires farless (if any) blow off pressure from the drum 400. As the puck 610passes the tangential point, each of the zones 1-10 are selectivelyturned on in an acquisition sequence, in order to gain control of thepatch as the puck 610 rolls past the drum 400.

A rotating valve disk 600 is used to rapidly control the application ofvacuum air to each individual zone 1-10 in a controlled way. Bysequential vacuum engagement, the undesirable low pressure zone at thetransfer point between drum 400 and 610 is minimized if not eliminated,and there is therefore less turbulence or disruption of a carried patchat that point. Incorporating a valve mechanism 600 that can quicklyswitch airflow passages between a vacuum supply chamber and atmospherein the puck 610 reduces the level of the air passage lengths to a levelthat will enable adequately rapid response. This allows for on/off time.of zones 1′-10′ to be nearly instantaneously controlled because of theproximity between the vacuum commutation and the vacuum surface of thepuck 610. This proximity also enables a rotating puck 610 to havemultiple air flow zones 1-10 which can be controlled to switch theairflow direction at the surface of the puck 610. By using multiplezones 1-10, airflow at the surface of the puck 610 can be optimized. toclosely approximate the airflow characteristics of a two roll systemshown in FIG. 15.

By locating the rotating valve disk 600 or other form of vacuum controlinside of the puck 610 assembly itself or in close proximity to thepuck, this puts the mode of control into the puck 610, and minimizes lagtime for on/off operations. Zone control in the puck 610 is adjacent tothe puck surface.

Still referring to FIG. 18, internal air passages 602 from valve disk600 are used commute vacuum from ports 502 to the surface of puck 610.

Drum 400 displays a transition position where air flow directionswitches from inward (arrows pointing into drum 400) to outward (arrowspointing out of drum 400). In a preferred embodiment, this transitionposition is offset either upstream or downstream of the discrete articletransfer (handoff by acquisition or deposition) positions by a selectedamount, to compensate for variations in the system.

Sill referring to FIG. 18, the rotatably driven multi-zoned vacuum puck610 used to turn discrete articles 180 degrees and transport them from apickup position (where for example a leading edge or zone 1′ of puck 610first begins acquisition of discrete articles, see, e.g., acquisitionpoint 52 of FIG. 1) to a deposition position (where for example discretearticles are laid down on a running web, see, e.g., deposition point 54of FIG. 1). The repositioning of articles shown for example in FIGS.5-17 of U.S. Pat. No. 8,016,972, incorporated herein by reference. Anexternal vacuum manifold (not shown) applies vacuum through internalvacuum passages to zones 1′-10′ in the puck as previously described whenthe zones 1′-10′ are located in positions between just upstream of theacquisition position, to the downstream side of the acquisitionposition, and the upstream side of the deposition position. When avacuum passage 1′-10′ is engaged with the vacuum manifold, ambient airflows into the pores on the surface of the puck 610 in order to holdmaterial against the puck's external surface. Conversely, when a vacuumpassage 1′-10′ is not engaged with the vacuum manifold, ambient airflows can flow out of the pores 24 on the surface of the puck 610.

To accomplish this, the vacuum puck 610 rotates such that the surface ofthe puck 610 is traveling at the same speed as the incoming discreteelement carried by drum 400. The external vacuum manifold is positionedsuch that ambient air flows outward through the surface of the puck 610at points immediately upstream of the acquisition point and ambient airflows inward through the pores in the surface of the puck 610 at pointsimmediately downstream of the pick-up point. As the leading edge of thediscrete article reaches the acquisition point, air flowing from theatmosphere into the vacuum puck 610 forces the leading edge of thediscrete article to transfer to and be held against the surface of thepuck 610. Likewise, the remainder of the discrete article will transferonto the porous roll or puck 610 as the porous roll or puck 610advances.

After the trailing edge of the discrete article is transferred to thesurface of the vacuum puck 610, the puck continues to rotate and therebytransports the discrete article to the deposition point. The vacuumapplied external vacuum manifold ends immediately upstream of thedeposition point such that ambient air flows into the puck 610 upstreamof the deposition point and ambient air flows out of the puck 610downstream of the deposition point. As the leading edge of the discretearticle passes the deposition point, air flowing out of the puck 610 andinto the vacuum zone of the receiving device forces the discrete articleto transfer from the surface of the porous roll onto the receivingdevice. Likewise, the remainder of the discrete article transfers ontothe receiving device as the discrete article continues to advance. Afterthe discrete article has transferred to the receiving device, the vacuumpuck returns to its original orientation and position upstream of thepickup point and the cycle repeats.

Likewise, the remainder of the discrete article transfers onto thereceiving device as the discrete article continues to advance. After thediscrete article has transferred to the receiving device, the vacuumpuck returns to its original orientation and position upstream of thepickup point and the cycle repeats. In such a puck system, ambient aircan flow from the inside of the puck outward to: 1) eliminate orminimize overlapping low pressure zones which in turn eliminates orminimizes in-rushes of air at the edges of the patch; 2) results in anairflow direction that is approximately perpendicular to the surface towhich the discrete element is riding upon. Such a puck system also canutilize micro-pores to: 1) reduce airflow requirements; 2) provide morecomplete sealing of the pores and thereby increases holding force on thediscrete article; and 3) minimize dead zones between pores to minimizethe potential for discrete article edge flip backs.

Referring now to FIG. 19, a perspective view of puck 610 is shown. Puck610 is advantageously equipped with micro vacuum commutation ports 24,which commute vacuum, for instance by the arrangement shown in FIG. 18.

Referring now to FIG. 20, an exemplary puck 610 is shown with thecapability of both rotation and revolution, as previously described.

FIGS. 21A-21F display a side view of a sequence of operation of an anvil900/drum 902 feeding discrete pieces 50A, 50B to a series of porousroll/internal vacuum manifold combinations 10/12/14A and 10/12/14Bpositioned about the drum 902 for passing and spacing discrete pieces50A and 50B to a running web 60. Porous roll/internal vacuum manifoldcombinations 10/12/14 are preferably operable as described previously,with manifold 14 rotating independently of roll 12, allowing therotational velocities of each to vary from one another (V2 for manifold14, and V3 for roll 12) and create unique operational sequences. Onesuch unique sequence is the operation displayed in FIGS. 21A-21F.

Referring first to FIG. 21A, an incoming web 49 is carried by a conveyor30 to an anvil 900/drum 902 combination. Incoming web 49 is severed intosequential alternating discrete pieces 50 a, and 50B, and this operationcan be a slip/cut technique as is known in the art.

In one embodiment, porous roll/internal vacuum manifold combinations10/12/14A and 10/12/14B are positioned about drum 902. In theillustrated embodiment, two porous roll/internal vacuum manifoldcombinations 10/12/14A and 10/12/14B are used, although more or lesscould be deployed depending on the desired operational sequence. A firstporous roll/internal vacuum manifold combination 10/12/14A is positionedupstream of a second porous roll/internal vacuum manifold combinations10/12/14B. The first porous roll/internal vacuum manifold combination10/12/14A is positioned and operated to pick up every other of thediscrete pieces 50A and 50B, the first combination picking up discretepieces 50A leaving behind discrete pieces 50B for the second porousroll/internal vacuum manifold combination 10/12/14B to acquire,accelerate and deposit. Preferably simultaneously, each of the porousroll/internal vacuum manifold combinations 10/12/14A and 10/12/14Bacquire discrete pieces 50A and 50B, respectively at their ownacquisition points 52, as shown in FIG. 21B.

Both porous roll/internal vacuum manifold. combinations 10/12/14A and10/12/14B then accelerate discrete pieces 50A and 50B, respectively totheir deposition points 54. At deposition points 54, discrete pieces 50Aand 50B are deposited. onto an incoming web 60 as shown in FIG. 21E, andthe incoming web can come into contact with discrete pieces 50A and 50Bby either a close-gap spacing arrangement between porous roll/internalvacuum manifold combinations 10/12/14A and 10/12/14B and the web, or abump method such as disclosed in U.S. Pat. No. 7,811,403 incorporatedherein by reference. Alternatively, a nip point underneath depositionpoints 54 could be ultrasonic bonding stations (not shown), which couldthen bond discrete pieces 50A and 50B to traveling web 60 simultaneouslywith deposition. This sequence allows for discrete pieces 50A and 50B tobe deposited onto running web 60 at a first spacing D1 between pieces50A and 50B, and allows for a second spacing D2, preferably productpitch, between two pieces 50A in a sequence and spacing D2 also betweentwo pieces 50B in a sequence. D1 and D2 can also be arranged so that D2is twice D1. The web as shown in FIG. 22 can then be severed intoindividual products at several locations, either through pieces 50Aand/or 50B, or between any of 50A and 50B, as desired.

As shown in FIG. 22, a top perspective view of an exemplary placementsequence of discrete pieces 50A and 50B about sides of a running web 60,a pair of discrete pieces 50A, and a pair of discrete pieces 50B can bedeposited at the same placement in a machine direction, for instance inplacement of ear tabs or other discrete components about a chassis web60 of a diaper. Products as shown in FIG. 22 can then be severed in thecross machine direction, either between

To accomplish a D1/D2 placement of discrete pieces 50A and 50B as shownin FIG. 22, FIG. 23 shows an exemplary transfer drum velocity speedprofile for porous roll/internal vacuum manifold combinations 10/12/14Aand 10/12/14B during an acquisition and deposition sequence. AlthoughFIG. 23 displays an exemplary transfer drum velocity speed profile forporous roll/internal vacuum manifold combinations 10/12/14A and10/12/14B, actual speeds can vary higher or lower than those displayed.As can be seen, referring to FIG. 23 as well as the sequence depicted inFIGS. 21A-21F, during a period of acquisition of an individual patch 50,the transfer drum moves at a constant velocity, preferably the samevelocity as the drum 902. During this period, referring for example toV1 (representing in this embodiment the velocity of drum 902), V2(representing in this embodiment the velocity of manifold 14), V3(representing in this embodiment the velocity of porous roll 12), and V4(representing in this embodiment the velocity of web 60) of FIG. 6,V1=V2=V3<V4. At the completion of patch 50 acquisition by one of theporous roll/internal vacuum manifold. combinations 10/12/14A and10/12/14B, the porous roll/internal vacuum manifold combination10/12/114 accelerates to equal V4 of the running web 60, until adeposition period of deposition of patch 50 to web 60, when V1<V2=V3=V4.Next, in preparation for acquisition of the next patch 50 in sequence,porous roll/internal vacuum manifold combinations 10/12/14A and10/12/14B decelerate back to equal V1. The process then repeats.

As multiple porous roll/internal vacuum manifold combinations 10/12/14Aand 10/12/14B work in conjunction, each porous roll/internal vacuummanifold combinations 10/12/14A and 10/12/14B processing every otherdiscrete article 50A or 50B in a continuous stream of discrete articles50 to change the spacing between discrete articles 50A and 50B, orsuccessive discrete articles 50A, by large amounts such as a 5:1 spacingincrease. In this manner, at least two spacings, D1 and D2, can beachieved between successive pieces.

The foregoing is considered as illustrative only of the principles ofthe invention. Furthermore, since numerous modifications and changeswill readily occur to those skilled in the art, it is not desired tolimit the invention to the exact construction and operation shown anddescribed. While the preferred embodiment has been described, thedetails may be changed without departing from the invention, which isdefined by the claims.

We claim:
 1. A system for transferring discrete web portions comprising: a drum carrying a plurality of discrete web portions comprising a first web portion and a second web portion; a first transfer roll in selective vacuum commutation with said plurality of discrete web portions; a second transfer roll in selective vacuum commutation with said plurality of discrete web portions, said second transfer roll arranged downstream in a machine direction from said first transfer roll; said first transfer roll acquiring said first web portion by said selective vacuum commutation, and not acquiring said second web portion; said second transfer roll acquiring said second web portion; said first and second transfer rolls depositing said first and second web portions onto a running web.
 2. A system for transferring discrete web portions according to claim 1, wherein said first and second transfer rolls deposit said first and second web portions onto a running web simultaneously.
 3. A system for transferring discrete web portions according to claim 1, said drum carrying said plurality of discrete web portions comprising a third web portion and a fourth web portion.
 4. A system for transferring discrete web portions according to claim 3, said first transfer roll acquiring said third web portion by said selective vacuum commutation, and not acquiring said fourth web portion; said second transfer roll acquiring said fourth web portion; said first and second transfer rolls depositing said third and fourth web portions onto a running web.
 5. A system for transferring discrete web portions according to claim 3, said first and second web portions spaced apart in said machine direction by a first spacing, said third and fourth web portions spaced apart in said machine direction by said first spacing, and said second and third web portions spaced apart in said machine direction by a second spacing at least one of shorter and longer than said first spacing. 